U.S. patent application number 12/861503 was filed with the patent office on 2011-03-03 for relay backhaul in wireless communication.
This patent application is currently assigned to FutureWei Technologies, Inc.. Invention is credited to Yufei Blankenship, Jianmin Lu.
Application Number | 20110051654 12/861503 |
Document ID | / |
Family ID | 43624788 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110051654 |
Kind Code |
A1 |
Blankenship; Yufei ; et
al. |
March 3, 2011 |
Relay Backhaul in Wireless Communication
Abstract
In one embodiment, a method for wireless communication includes
transmitting a first system information for a subframe structure
from a controller to a relay node. The first system information
includes radio resource configuration for a downlink backhaul link.
The subframe structure includes a physical downlink control channel
(PDCCH) region for user equipments and a separate relay physical
downlink control channel (R-PDCCH) region for relay nodes.
Inventors: |
Blankenship; Yufei;
(Kildeer, IL) ; Lu; Jianmin; (San Diego,
CA) |
Assignee: |
FutureWei Technologies,
Inc.
Plano
TX
|
Family ID: |
43624788 |
Appl. No.: |
12/861503 |
Filed: |
August 23, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61237575 |
Aug 27, 2009 |
|
|
|
Current U.S.
Class: |
370/315 |
Current CPC
Class: |
H04B 7/2606 20130101;
H04W 84/047 20130101; H04W 72/042 20130101; H04W 92/045 20130101;
H04L 5/0092 20130101; H04L 5/0035 20130101; H04B 7/2656 20130101;
H04L 5/0005 20130101 |
Class at
Publication: |
370/315 |
International
Class: |
H04B 7/14 20060101
H04B007/14 |
Claims
1. A method for wireless communication comprising: transmitting a
first system information for a subframe structure from a controller
to a relay node, the first system information comprising radio
resource configuration for a downlink backhaul link, wherein the
subframe structure comprises a physical downlink control channel
(PDCCH) region for user equipments and a separate relay physical
downlink control channel (R-PDCCH) region for relay nodes.
2. The method of claim 1, wherein the subframe structure comprises
a physical downlink shared channel (PDSCH) for user equipments and
a separate relay physical downlink shared channel (R-PDSCH) for
relay nodes.
3. The method of claim 1, further comprising using a subframe
having the subframe structure for a downlink backhaul
transmission.
4. The method of claim 1, further comprising receiving the first
system information at the relay node, wherein the relay node uses
the first system information to set up the downlink backhaul link
from the controller to the relay node.
5. The method of claim 1, wherein the radio resource configuration
comprises information indicating a number of OFDM symbols used for
the R-PDSCH.
6. The method of claim 1, wherein the radio resource configuration
comprises information indicating a number of OFDM symbols used for
the R-PDCCH.
7. The method of claim 1, wherein the radio resource configuration
comprises information indicating a number of resource blocks for
the R-PDCCH.
8. The method of claim 1, wherein the controller further transmits
the timing information of the downlink backhaul link to the relay
node.
9. The method of claim 8, wherein the timing information comprises
a duration of time during which the first system information is
valid, and/or a period of the downlink backhaul link.
10. The method of claim 8, wherein the timing information comprises
a bitmap to indicate the subframes available for the downlink
backhaul link.
11. The method of claim 1, wherein the first system information is
transmitted using unicasting.
12. The method of claim 11, wherein the first system information is
transmitted via radio resource control (RRC) signaling.
13. The method of claim 1, further comprising transmitting a second
system information from the controller to a second relay node.
14. A method for wireless communication comprising: transmitting a
first system information for a subframe structure from a controller
to a first relay node, the first system information comprising
radio resource configuration for a uplink backhaul link, wherein
the subframe structure comprises a relay physical uplink shared
channel (R-PUSCH) for relay nodes and a physical uplink shared
channel (PUSCH) for user equipments, and wherein the R-PUSCH and
the PUSCH are frequency division multiplexed within the subframe
structure.
15. The method of claim 14, further comprising using subframes
having the subframe structure for an uplink backhaul
transmission.
16. The method of claim 14, wherein the radio resource
configuration comprises information indicating a number of Discrete
Fourier Transform Spread OFDM (DFT-SOFDM) symbols for the
R-PUSCH.
17. The method of claim 14, wherein the first system information is
transmitted through unicasting.
18. The method of claim 17, wherein the first system information is
transmitted by RRC signaling.
19. The method of claim 14, further comprising transmitting a
second system information from the controller to a second relay
node, the second system information comprising radio resource
configuration for a second uplink backhaul link.
20. A method for wireless communication comprising: unicasting a
first system information for a subframe structure from a donor base
station to a relay node using radio resource control signaling, the
first system information comprising radio resource configuration
for a first downlink backhaul link, wherein the subframe structure
comprises a physical downlink control channel (PDCCH) region for
user equipments and a separate relay physical downlink control
channel (R-PDCCH) region for relay nodes.
21. The method of claim 20, wherein the subframe structure further
comprises a relay physical downlink shared channel (R-PDSCH)
region, and wherein the R-PDCCH region and the R-PDSCH region
follow a physical downlink control channel PDCCH region in the
subframe structure.
22. The method of claim 20, further comprising: unicasting a second
system information from the donor base station to the relay node
using radio resource control signaling, the second system
information comprising radio resource configuration for the same
downlink backhaul link, wherein the second system information is
transmitted after the first system information.
23. The method of claim 22, wherein the relay node replaces the
first system information with the second system information.
24. The method of claim 20, further comprising: receiving the first
system information at the relay node; and using subframes having
the subframe structure for the downlink backhaul link.
25. The method of claim 20, wherein the first system information
further comprises timing information for the downlink backhaul
link.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/237,575, filed on Aug. 27, 2009, entitled "Relay
Backhaul in Wireless Communication," which application is hereby
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates generally to wireless
communication, and more particularly to relay backhaul in wireless
communication.
BACKGROUND
[0003] Wireless communication systems are widely used to provide
voice and data services for multiple users using a variety of
access terminals such as cellular telephones, laptop computers and
various multimedia devices. Such communications systems can
encompass local area networks, such as IEEE 801.11 networks,
cellular telephone and/or mobile broadband networks. The
communication system can use one or more multiple access
techniques, such as Frequency Division Multiple Access (FDMA), Time
Division Multiple Access (TDMA), Code Division Multiple Access
(CDMA), Orthogonal Frequency Division Multiple Access (OFDMA),
Single Carrier Frequency Division Multiple Access (SC-FDMA) and
others. Mobile broadband networks can conform to a number of system
types or partnerships such as, General Packet Radio Service (GPRS),
3rd-Generation standards (3G), Worldwide Interoperability for
Microwave Access (WiMAX), Universal Mobile Telecommunications
System (UMTS), the 3rd Generation Partnership Project (3GPP),
Evolution-Data Optimized EV-DO, or Long Term Evolution (LTE).
[0004] Some systems, such as LTE, strive to serve densely populated
areas with very high data rates. One way in which an LTE network
can provide dense coverage and high data capacity in a cost
effective manner is to utilize Relay Nodes (RNs), which function as
base stations to user devices, but do not have wired backhaul
connections as base stations do. Instead, the RN communicates
wirelessly with an LTE base station (eNB) via a standard LTE radio
link. Base station (BS) is also commonly referred to as evolved
nodeB (eNB), base transceiver station, controller, access point
(AP), access network (AN), and so forth, while a user device or
user equipment (UE) may also be commonly referred to as mobile
station (MS), access terminal (AT), subscribers, subscriber
stations, terminals, mobile stations, and so on.
[0005] Because a RN behaves as both a UE and an eNB, the RN
requires significant system information that must be wirelessly
transmitted for successful operation. Therefore, one of the
challenges in incorporating relay nodes involves transferring such
information to the RNs.
SUMMARY OF THE INVENTION
[0006] These and other problems are generally solved or
circumvented, and technical advantages are generally achieved, by
illustrative embodiments of the present invention.
[0007] In accordance with an embodiment of the present invention, a
method for wireless communication comprises a method for wireless
communication includes transmitting system information for a
subframe structure from a controller to a relay node. The first
system information includes radio resource configuration for a
downlink backhaul link. The subframe structure includes a physical
downlink control channel (PDCCH) region for user equipments and a
separate relay physical downlink control channel (R-PDCCH) region
for relay nodes.
[0008] In another embodiment of the present invention, a method for
wireless communication comprises transmitting a first system
information for a subframe structure from a controller to a first
relay node. The first system information comprises radio resource
configuration for a uplink backhaul link. The subframe structure
comprises a relay physical uplink shared channel (R-PUSCH) for
relay nodes and a physical uplink shared channel (PUSCH) for user
equipments. The R-PUSCH and the PUSCH are frequency division
multiplexed within the subframe structure.
[0009] In yet another embodiment of the present invention, a method
for wireless communication comprises unicasting a first system
information for a subframe structure from a donor base station to a
relay node using radio resource control signaling. The first system
information comprises radio resource configuration for a first
downlink backhaul link. The subframe structure comprises a physical
downlink control channel (PDCCH) region for user equipments and a
separate relay physical downlink control channel (R-PDCCH) region
for relay nodes. The subframe structure further comprises a relay
physical downlink shared channel (R-PDSCH) region.
[0010] The foregoing has outlined rather broadly the features of an
embodiment of the present invention in order that the detailed
description of the invention that follows may be better understood.
Additional features and advantages of embodiments of the invention
will be described hereinafter, which form the subject of the claims
of the invention. It should be appreciated by those skilled in the
art that the conception and specific embodiments disclosed may be
readily utilized as a basis for modifying or designing other
structures or processes for carrying out the same purposes of the
present invention. It should also be realized by those skilled in
the art that such equivalent constructions do not depart from the
spirit and scope of the invention as set forth in the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawing, in
which:
[0012] FIG. 1 illustrates a wireless communications system in
accordance with embodiments of the invention;
[0013] FIG. 2 illustrates a relay-to-UE communication using normal
subframes and eNB-to-relay communication using MBSFN subframes;
[0014] FIG. 3 illustrates a frame structure for a downlink
transmission from an eNB to a RN in accordance with an embodiment
of the invention;
[0015] FIG. 4 illustrates another embodiment for a downlink
transmission;
[0016] FIG. 5 illustrates an embodiment for an uplink
transmission;
[0017] FIG. 6 illustrates operations at the relay node and the eNB
in accordance with an embodiment of the invention;
[0018] FIG. 7 illustrates a block diagram of an embodiment of the
eNB; and
[0019] FIG. 8 illustrates a block diagram of an embodiment of the
relay node.
[0020] Corresponding numerals and symbols in the different figures
generally refer to corresponding parts unless otherwise indicated.
The figures are drawn to clearly illustrate the relevant aspects of
the embodiments and are not necessarily drawn to scale.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0021] The making and using of various embodiments are discussed in
detail below. It should be appreciated, however, that the present
invention provides many applicable inventive concepts that can be
embodied in a wide variety of specific contexts. The specific
embodiments discussed are merely illustrative of specific ways to
make and use the invention, and do not limit the scope of the
invention.
[0022] A Relay Node (RN) is considered as a tool to improve, e.g.,
the coverage of high data rates, group mobility, temporary network
deployment, the cell-edge throughput and/or to provide coverage in
new areas. The RN is wirelessly connected to a wireless
communications network via a donor cell (also referred to as a
donor enhanced Node B (donor eNB or D-eNB)), and the link between
RN and the donor eNB is referred to as the backhaul link. The RN
may serve as an eNB to one or more User Equipment (UE), and the
link between the RN and the UE is referred to as the access
link.
[0023] The RN may appear identical to an eNB to the UE that is
being served by the RN. Similar to an eNB, the RN schedules uplink
(UL) and downlink (DL) transmissions to the UE over an access link
between the RN and the UE. When a UE is served by more than one RN,
Cooperative Multipoint Transmission/Reception (CoMP) may be made by
multiple RNs, which may help to provide cooperative gain and
improve the performance of the UE.
[0024] FIG. 1 illustrates a wireless communications system 100 in
accordance with embodiments of the invention. Wireless
communications system 100 includes a D-eNB 105, a RN A 110, and a
RN B 111. RN A 110 and RN B 111 may be connected over a wireless
backhaul link to D-eNB 105. The wireless connection between D-eNB
105 and RN A 110 (or RN B 111) may be referred to as a backhaul
link. RN A 110 and RN B 111 belong to D-eNB 105 and may receive
transmission grants (which assigns network resources) from D-eNB
105.
[0025] Wireless communications system 100 also includes UE A 115
and UE B 116. UE A 115 and UE B 116 may be wirelessly connected to
both RN A 110 and RN B 111. The wireless connection between a UE
and a RN (e.g., UE A 115 and RN A 110, UE B 116 and RN B 111, UE A
115 and RN B 111, UE B 116 and RN A 110, etc.) may be referred to
as an access link. Furthermore, in addition to access links, a UE
may be wirelessly connected to a D-eNB (e.g., UE A 115 and D-eNB
105).
[0026] The connection between the network and the relay node can be
in-band, in which the network-to-relay link share the same band
with direct network-to-UE links within the donor cell. LTE Rel-8
UEs should be able to connect to the donor cell in this case.
Alternatively, the connection can be out-band, in which case the
network-to-relay link does not operate in the same band as direct
network-to-UE links within the donor cell.
[0027] With respect to the knowledge in the UE, relays can be
classified as transparent, in which case the UE is not aware of
whether or not it communicates with the network via the relay.
Alternatively, relays can be non-transparent, in which case the UE
is aware of whether or not it is communicating with the network via
the relay.
[0028] Type-1 relay nodes are part of LTE-Advanced. A type-1 relay
node is an in-band relaying node characterized by the following.
Each type-1 control cell appears to a UE as a separate cell
distinct from the donor cell. The cells have their own Physical
Cell ID (defined in LTE Rel-8) and the relay node transmits its own
synchronization channels, reference symbols, etc. In the context of
single-cell operation, the UE shall receive scheduling information
and HARQ feedback directly from the relay node and send its control
channels (SR/CQI/ACK) to the relay node. The type-1 RN is backward
compatible e.g., appears as a Rel-8 eNB to Rel-8 UE. To
LTE-Advanced UEs, type-1 relay node must appear different from
Rel-8 eNB to allow for further performance enhancement.
[0029] Therefore, in order to allow in-band backhauling of the
relay traffic on the relay-eNB link, some resources in the
time-frequency space are set aside for this link and cannot be used
for the access link on the respective node.
[0030] For in-band relaying, the eNB-to-relay link operates in the
same frequency spectrum as the relay-to-UE link. Due to the relay
transmitter causing interference to its own receiver, simultaneous
eNB-to-relay and relay-to-UE transmissions on the same frequency
resource may not be feasible unless sufficient isolation of the
outgoing and incoming signals is provided, e.g., by means of
specific, well separated and well isolated antenna structures.
Similarly, at the relay node it may not be possible to receive UE
transmissions simultaneously with the relay transmitting to the
eNodeB.
[0031] The interference problem is handled by operating the relay
node such that the relay node is not transmitting to terminals when
it is supposed to receive data from the donor eNB, i.e., to create
"gaps" in the relay-to-UE transmission. These "gaps" during which
terminals (including Rel-8 terminals) are not supposed to expect
any relay transmission are created by configuring multicast
broadcast single frequency network approach (MBSFN) subframes as
illustrated for example in FIG. 2. As illustrated in FIG. 2,
relay-to-eNB transmissions can be facilitated by not allowing any
terminal-to-relay transmissions in some subframes. FIG. 2
illustrates an example of relay-to-UE communication using normal
subframes (left) and eNB-to-relay communication using MBSFN
subframes (right).
[0032] FIG. 3 illustrates a frame structure for a downlink
transmission from an eNB to a RN in accordance with embodiments of
the invention. The downlink subframe includes a physical downlink
control channel (PDCCH) and a physical downlink shared channel
(PDSCH). The PDSCH is shown to include data intended for UE1, which
is served directly by the eNB. Since the DL subframe is also a DL
relay backhaul link, the subframe includes some REs dedicated for
use as the DL relay backhaul link, such as relay-physical downlink
control channel (R-PDCCH) and relay-physical downlink shared
channel (R-PDSCH). Here, PDCCH is used for transmitting downlink
control information from the eNB to a regular UE. PDSCH is used for
transmitting downlink data packets from the eNB to a regular UE.
R-PDCCH is used for transmitting downlink control information from
the eNB to a RN for the backhaul link. R-PDSCH is for transmitting
downlink data packets from the eNB to a RN for the backhaul
link.
[0033] In 3GPP LTE/LTE-A, each subframe is composed of a certain
number of OFDM symbols in time, and a number of OFDM subcarriers in
frequency. The resource in a subframe is allocated in the unit of a
resource block (RB). A RB comprises a number of OFDM symbols in
time, and 12 subcarriers in frequency. The RBs are allocated in a
pair, called a RB pair. Therefore, for simplicity, the RB pair
allocation is referred to as RB allocation.
[0034] System information delivery by eNB for relay is now
described in accordance with embodiments of the invention. To
enable the operation of relay nodes subordinate to a donor eNB,
some additional system information is needed for the relay node
(RN), on top of regular system information.
[0035] Additional information required by the relay node in
downlink transmissions is described in various embodiments of the
invention. For radio resource configuration, the additional
information may include the number of OFDM symbols used for
Physical Downlink Control Channel (PDCCH) (n.sub.0), R-PDCCH
(n.sub.1), the number of resource blocks (RBs) used for R-PDCCH,
the index of starting RBs used for R-PDCCH, and/or the type of
R-PDCCH that may be distributed or localized. Because R-PDSCH may
not start at the same OFDM symbol as R-PDCCH, the number of OFDM
symbols used for R-PDSCH may be provided by defining the position
of the starting symbol and the position of the ending symbol of
R-PDSCH. Similarly, the number of OFDM symbols used for R-PDCCH may
be provided by defining the starting symbol and the ending symbol
of R-PDCCH. In one embodiment, the R-PDCCH and the R-PDSCH end at
the same OFDM symbol and this information (e.g., position of the
ending symbol) only needs to be provided once.
[0036] In one or more embodiments, the number of OFDM symbols used
for PDCCH n.sub.0 may include a value. In one case, a value of
n.sub.0 may be 3. Similarly, in one case, a value for the number of
OFDM symbols used for R-PDCCH n.sub.1 may be 2. In general, the
radio resource configuration may include information indicating a
number of OFDM symbols used for PDSCH, and/or information
indicating a number of OFDM symbols for the R-PDCCH.
[0037] As illustrated in FIG. 3, the subframe comprises a separate
PDCCH region and a R-PDCCH region. The relay data packet (R-PDSCH)
and the regular UE data packet (PDSCH) share the same subframe, for
example, in a frequency-division multiplexing (FDM) fashion.
[0038] The timing information about the downlink backhaul resources
may also be included in various embodiments. The timing information
may include the time that these parameters are going to be
effective. This time can be provided by specifying a radio frame
number (SFN), and/or a subframe number. The time information may
also include the period of the downlink backhaul allocation (e.g.,
how frequently the subframe can be used for downlink backhaul),
and/or a bitmap to indicate the subframes that are available for
downlink backhaul.
[0039] Additional information for relay node in uplink is described
in various embodiments of the invention. Radio resource
configuration information may include the number of RBs used for
uplink backhaul, and/or the index of starting RB used for uplink
backhaul.
[0040] The timing information about the uplink backhaul resources
may include the time that the parameters are going to be effective.
This time can be provided by specifying a radio frame number (SFN),
and/or a subframe number. The timing information may also comprise
the period of the uplink backhaul allocation (e.g., how frequently
the subframe can be used for downlink backhaul), and/or a bitmap to
indicate the subframes that are available for uplink backhaul.
[0041] In various embodiments, the above system information is
delivered to RN from DeNB (donor cell) through either the
broadcasting way or unicasting way. For example, the radio resource
configuration and timing information for each RN might be
different. Consequently, the said parameters can be defined for
each RN individually, and this information is sent to each RN
individually via unicast. This scenario is possible if the
frequency selective R-PDCCH is adopted.
[0042] As described in 3GPP TS 36.331 V8.5.0 (2009-03), Evolved
Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control
(RRC); Protocol specification, which is incorporated by reference
herein, radio resource control (RRC) signalling may be used when
unicasting is desired. Therefore, in one or more embodiments, the
system information parameters are transmitted to each RN from the
donor eNB using radio resource control (RRC) signalling.
[0043] On the other hand, the radio resource configuration and
timing information can be the composite information for all RNs.
For example, the radio resource information may indicate the search
space that all RNs' control information may be located. In this
scenario, this information may be broadcasted by incorporating them
into a SIB (System Information Block). For example, a SIB 13 can be
defined for the relay node.
[0044] Since RN cannot read the regular PDCCH once it is
registered, it cannot read the regular SIBs broadcasted by DeNB. As
a consequence, in various embodiments, those parameters have to be
conveyed through the relay backhaul channels, as R-PDCCH or
R-PDSCH. In one embodiment, eNB contains all the necessary SIBs in
the payload of R-PDSCH. In another embodiment, eNB defines a new
SIB which contains all the necessary information, which contains,
for example, a configuration defining how relay will perform its
own cell selection and measurement. Consequently and
advantageously, the UEs served by the RN can go to sleep during
these subframes to save power, rather than being forced to perform
unnecessary measurement.
[0045] In various embodiments, sets of downlink and uplink
information are defined. Various means to convey such information
from eNB to relay nodes are designed in embodiments of the
invention.
[0046] FIG. 4 illustrates a subframe structure for a downlink
transmission from an eNB to a RN in accordance with an embodiment
of the invention.
[0047] Similar to the embodiment described with respect to FIG. 3,
the location of the R-PDCCH and the R-PDSCH are communicated. For
example, the number of OFDM symbols used for Physical Downlink
Control Channel (PDCCH), the number of OFDM symbols used for
R-PDCCH, the number of resource blocks (RBs) used for R-PDCCH, the
index of starting RBs used for R-PDCCH, and/or the type of R-PDCCH
where the type may be distributed or localized. However, in some
embodiments, the starting RB may be predetermined, and hence this
may not be necessary.
[0048] As in FIG. 3, the subframe comprises a separate PDCCH region
and R-PDCCH region. The relay data packet (carried on R-PDSCH) and
regular UE data packet (carried on PDSCH) share the same subframe
such that the R-PDSCH uses different frequency than the UE data
packet (PDSCH) (i.e., FDM fashion).
[0049] FIG. 5 illustrates a subframe structure for an uplink
transmission from a RN to an eNB in accordance with an embodiment
of the invention.
[0050] In various embodiments, the relay data packet (carried on
relay physical uplink shared channel R-PUSCH) and the regular data
packet (carried on physical uplink shared channel PUSCH) share the
same subframe. In other words, R-PUSCH and PUSCH are not separated
in time but only separated in frequency (i.e., frequency division
multiplexing).
[0051] Radio resource configuration information and timing
information about the uplink backhaul resources may be transmitted
to the RN from the donor eNB. In one embodiment, the radio resource
configuration information may include the number of RBs used for
the uplink backhaul, and/or the index of starting RB used for the
uplink backhaul. In one embodiment, the number of SC-FDMA symbols
used for R-PUSCH may be communicated from the donor eNB to the RN.
The timing information about the uplink backhaul resources may
include the time that the parameters are going to be effective.
This time can be provided by specifying a radio frame number (SFN),
and/or a subframe number. The timing information may also comprise
the period of the uplink backhaul allocation, and/or a bitmap to
indicate the subframes that are available for uplink backhaul.
[0052] FIG. 6 illustrates operations at the relay node and the eNB
in accordance with embodiments of the invention.
[0053] Referring to FIG. 6, step 610, a donor eNB transmits, e.g.,
unicasting or broadcasting, first system information to a first RN.
The first system information was described above using FIGS. 3-5
and may be for uplink and/or downlink transmission. The first RN
receives the first system information (step 620) and, e.g.,
determines the subframe structure to be used for the uplink and/or
downlink communication. The first RN sets up a backhaul link with
the eNB for the transmission (step 630), and may set up both
downlink and uplinks. For example, the first RN may communicate
with the donor eNB using subframes having the subframe structure.
The first RN may also use the first system information to set up an
access link with the UE (step 640). Communication between the UE
and the eNB progresses through the established backhaul link and
the access link.
[0054] In one or more embodiments, a second system information is
transmitted from the donor eNB to the first relay node. In one
embodiment, unicasting using radio resource control (RRC) signaling
is used to transmit the second system information. The second
system information comprises radio resource configuration for the
same downlink backhaul link established previously (e.g., in steps
630 and 640). In various embodiments, the second system information
is transmitted after the first system information. In one or more
embodiments, the relay node replaces the first system information
with the second system information, and the donor eNB and the first
relay node subsequently applies the second system information in
constructing the downlink and uplink subframes for the backhaul
link transmission.
[0055] In various embodiments, the donor eNB may further transmit a
third system information to a second relay node. The third system
information may comprise radio resource configuration for a second
downlink backhaul link or a second uplink backhaul link which are
used in backhaul communication between the donor eNB and the second
relay node.
[0056] A block diagram of an embodiment eNB 700 is illustrated in
FIG. 7. eNB 700 has eNB processor 704 coupled to transmitter (TX)
706 and receiver 708, and network interface 702. Transmitter 706
and receiver 708 are coupled to antenna 712 via coupler 710. The
eNB processor 704 executes embodiment methods and algorithms as
described above. In one or more embodiments, the embodiments of the
invention may be implemented within the transmitter 706, the
receiver 708, or as a separate circuitry. Some of the algorithms,
such as to implement the operations illustrated in FIGS. 3-5, may
also be implemented as software executed using the eNB processor
704. In one or more embodiments, the eNB 700 is configured to
transmit system information to a relay node. The system information
may comprise radio resource configuration and/or timing information
for downlink or uplink backhaul relaying.
[0057] In an embodiment, eNB 700 is configured to operate in a LTE
network using an OFDMA downlink and Discrete Fourier Transform
Spread OFDM (DFT-SOFDM) uplink channels. In alternative
embodiments, other systems, network types and transmission schemes
can be used, for example, 1XEV-DO, IEEE 802.11, IEEE 802.15 and
IEEE 802.16. The eNB 700 may have multiple transmitters, receivers
and antennas to support MIMO operation.
[0058] A block diagram of an embodiment relay node 800 is
illustrated in FIG. 8. Relay node 800 has donor antenna 820, which
transmits to and from the eNB and is coupled to coupler 818,
transmitter 822 and receiver 816. Service antenna 812, which
transmits to and receives signals from user devices, is coupled to
coupler 810, transmitter 806 and receiver 808. RN processor 814,
which is coupled to both the donor and UE signal paths, controls
the operation of relay node and implements embodiment algorithms
described herein.
[0059] In one or more embodiments, the embodiments of the invention
may be implemented within the transmitter 822, the receiver 816, or
as a separate circuitry. Some of the algorithms, such as to
implement the operations illustrated in FIGS. 3-5, may also be
implemented as software executed using the RN processor 814. In one
or more embodiments, the relay node 800 is configured to receive
system information from a donor base station. The system
information may comprise radio resource configuration and/or timing
information for downlink or uplink backhaul relaying. The relay
node 800 uses the system information to set up a subordinate relay
node for relaying.
[0060] In an embodiment of the present invention, relay node 800 is
configured to operate in a LTE network using an OFDMA downlink
channels divided into multiple subbands, and Single Carrier
Frequency Division Multiple Access (SC-FDMA) uplink divided into
multiple subbands. In alternative embodiments, other systems,
network types and transmission schemes can be used.
[0061] In one embodiment, a method for wireless communication
comprises transmitting system information for a subframe structure
from a donor base station to a relay node. The system information
comprises radio resource configuration and/or timing information
for downlink backhaul relaying. Subframes having the subframe
structure are used for the downlink backhaul transmission. The
downlink backhaul refers to the transmission link from the donor
base station to the relay node. The subframe structure comprises a
physical downlink control channel (PDCCH) region and a separate
relay physical downlink control channel (R-PDCCH) region.
[0062] In another embodiment, a method for wireless communication
comprises transmitting system information for a subframe structure
from a donor base station to a relay node. The system information
comprises radio resource configuration and/or timing information
for uplink backhaul transmission. The uplink backhaul refers to the
transmission link from the relay node to the donor base station.
Subframes having the subframe structure are used for the uplink
backhaul transmission. The subframe structure comprises a relay
physical uplink shared channel R-PUSCH and a physical uplink shared
channel PUSCH. The R-PUSCH and the PUSCH are not separated in time
but only in frequency within the subframe structure. In other
words, the R-PUSCH and the PUSCH are frequency division multiplexed
within the subframe structure
[0063] In yet another embodiment, a method for wireless
communication comprises unicasting a first system information for a
subframe structure from a donor base station to a relay node using
radio resource control signaling. The first system information
comprises radio resource configuration and/or timing information
for downlink backhaul relaying. Subframes having the subframe
structure are used for the downlink backhaul relaying. The subframe
structure comprises a physical downlink control channel (PDCCH)
region and a separate relay physical downlink control channel
(R-PDCCH) region. The subframe structure comprises a relay physical
downlink shared channel (R-PDSCH) region and a separate physical
downlink shared channel (PDSCH) region.
[0064] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims. For example, many of the features and functions
discussed above can be implemented in software, hardware, or
firmware, or a combination thereof.
[0065] Moreover, the scope of the present application is not
intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure of the present invention, processes, machines,
manufacture, compositions of matter, means, methods, or steps,
presently existing or later to be developed, that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention. Accordingly, the
appended claims are intended to include within their scope such
processes, machines, manufacture, compositions of matter, means,
methods, or steps.
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